Edge card interconnection systems are known for interconnecting modules with electronic printed circuit boards. Known modules, such as single in-line memory modules (SIMM) and electronic sub-assembly daughter board modules require interconnection with a main electronic module or mother board, which typically involves implementing an edge connection scheme wherein contact pads on the edge of the module are engagable with contacts in a connector or socket on the main module or motherboard.
Implementations such as the EISABUS Connector, illustrated in FIG. 1, and a typical SIMM socket, illustrated in FIG. 2, effect a connection to a module or card edge which results in electrical contacts 10, 10' accommodating or absorbing tolerances associated with the module thickness (i.e. board thickness tolerance). As illustrated in FIGS. 1 and 2, prior art connectors receive modules having contact pads which are accommodated by a contact gap 12 within the mating connector. The contact gap 12 is typically of a lesser dimension than the thickness of the module so that the contacts 10, 10' deflect upon receipt of the module within the contact gap 12. Thus, the contacts absorb the entire board thickness tolerance of the module and must be configured to accommodate varying thicknesses due to the typical non-uniformity of module thickness. Generally, contacts are sufficiently dimensioned, e.g. are made longer, so as to permit sufficient deflection to accommodate thickness tolerances. Such contacts, which may be longer than is absolutely necessary, introduce undesirable propagation delay to an electrical signal as it is conducted through the connector. Further, frequent deflection of such unnecessarily long contacts results in degradation of the resiliency of the contact which causes the contact gap to undesirably expand and diminish contact integrity.
Known edge card interconnection systems, such as the one illustrated in FIGS. 3 and 3A, also typically have a latching mechanism which serves to maintain a module, such as a SIMM, in alignment within the connector. Known latches 14 typically reside within a cavity or behind walls in the connector body and are constrained in configuration by the connector members or walls which contain the latch. Such latches, like the contacts known in the prior art, are subject to resiliency degradation over time as a result of frequent deflection. Known latches, especially when disposed within a recess, are difficult to manually access and manipulate for extracting a module from the connector. Further, known latches typically require that the module being engaged have a hole 16 or latch engagement feature for receiving a module engagement portion 18 of the latch. As latch resiliency degrades and/or the latch 14 becomes loosened within its recess, alignment of the latch engagement hole and the latch becomes evermore difficult resulting in module alignment problems and electrical contact degradation. Further, latch engaging holes proximate to a module edge, may create vulnerable areas of the module. Such vulnerable module areas, when left unprotected and exposed to the forces associated with manual manipulation of the latch for extraction, may be susceptible to breakage.
Additionally, known edge card interconnection systems typically incorporate hold-down mechanisms for attaching the connector, usually by epoxy or soldering, to a circuit board. A known hold-down mechanism, as illustrated in FIG. 4 is an integral plastic member 20 which is epoxied to the circuit board 22 for holding the connector housing in place. However, epoxied integral plastic members are difficult to remove from the printed circuit board without causing damage to the board and/or the protuberance.
Alternatively, a solderable protrusion 24, such as illustrated in FIG. 4A, is integrated with the housing and is soldered to a through-hole in the printed circuit board to secure the connector thereto. Solderable protuberances are typically non-compliant and rely heavily on a butt solder joint to maintain hold-down engagement with the printed circuit board. As the solderable member must be dimensioned to fit easily into through-holes of various tolerances, significant gaps between the protuberance and the through-hole may be present, causing difficulty in soldering and diminishing the integrity of the hold-down.